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A146034 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation. 0

%I

%S 1,1,1,3,3,7,15,43,83,271,633,3283,9541,54293,204827,1408893,6437305,

%T 54681853,303651861,3282191633,22628378377,297350762879,2544553561975,

%U 41024771076465,431789004830701,8608866149320377,111456693040140865

%N Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.

%e Maximal 8 X 8 example

%e .0.0.1.0.0.1.1.1

%e .0.0.1.0.1.0.0.1

%e .1.1.1.0.1.0.0.1

%e .0.0.0.0.1.1.1.0

%e .0.1.1.1.0.0.0.0

%e .1.0.0.1.0.1.1.1

%e .1.0.0.1.0.1.0.0

%e .1.1.1.0.0.1.0.0

%K nonn

%O 1,4

%A _R. H. Hardin_, Oct 26 2008

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Last modified May 18 03:15 EDT 2022. Contains 353779 sequences. (Running on oeis4.)